Quartz resonator pressure transducers and methods of operation

Patent metadata

Field	Value
Publication number	US-9528896-B2
Application number	US-201313839238-A
Country	US
Kind code	B2
Filing date	Mar 15, 2013
Priority date	Mar 15, 2013
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

A cylindrical quartz crystal transducer that exhibits a low probability of twinning, and uses a combination of resonator signal inputs at the B-mode and C-mode frequencies to calculate resonator temperature. Crystallographic orientations are disclosed where combinations of B-mode and C-mode resonant frequencies exist that are sufficiently independent of pressure to enable accurate calculation of temperature under transient conditions. Such a transducer is usable at higher pressures and temperatures than conventional quartz pressure transducers. Furthermore, because the structure allows a choice of crystallographic orientation, other characteristics of the transducer, such as increased pressure sensitivity and activity dip-free operation, may be optimized by varying crystallographic orientation.

First claim

What is claimed is:

1. A dual-mode pressure transducer, comprising:
a quartz crystal structure having a crystallographic orientation, wherein the quartz crystal structure comprises:
a double cut comprising:
a first cut having a first angular displacement (phi) about the X-axis of 26°; and
a second cut having a second angular displacement (theta) about the Z-axis between 33° and 34°;

a substantially cylindrical body having a longitudinal bore; and
a disc-shaped resonator carried by the body and extending transversely across the longitudinal bore; and

an electronics assembly in communication with the quartz crystal structure, the electronics assembly configured to:
drive the resonator;
receive signal inputs from the resonator from a non-fundamental B-mode resonant frequency primarily dependent on temperature;
receive other signal inputs from the resonator from a non-fundamental C-mode resonant frequency primarily dependent on pressure; and
calculate pressure-independent temperature under transient conditions using a combination of the signal inputs and the other signal inputs to compensate for the pressure determined from the non-fundamental C-mode resonant frequency.

2. The pressure transducer of claim 1 , wherein the disc-shaped resonator is integral with the body, and further including end caps secured to the body across opposing ends of the longitudinal bore.

3. The pressure transducer of claim 1 , wherein the body comprises first and second end caps, each end cap defining a portion of the longitudinal bore on opposing sides of the disc-shaped resonator and having the disc-shaped resonator secured therebetween.

4. The pressure transducer of claim 1 , wherein the resonator is a 3 rd overtone blank with a contour of 2.5 diopters on both sides.

5. A method of measuring a temperature-compensated pressure using a quartz crystal structure, the method comprising:
stimulating, under transient temperature conditions, the disc-shaped resonator of the quartz crystal structure of the dual-mode pressure transducer of claim 1 under external pressure applied to the quartz crystal structure to provide signal inputs from a non-fundamental B-mode resonant frequency and a non-fundamental C-mode resonant frequency; and
using a combination of the signal inputs to compensate a pressure determined from the non-fundamental C-mode resonant frequency signal input.

6. The method of claim 5 , wherein using a combination of the signal inputs comprises using a sum of the signal inputs.

7. The method of claim 5 , wherein the non-fundamental B-mode resonant frequency and the non-fundamental C-mode resonant frequency is the 3 rd harmonic of each mode.

8. The method of claim 5 , further comprising determining a change in temperature with the following equation:

Δ
⁢

⁢
T

=

(

f

C
⁢

+

Kf
B

-

f

C
⁢

⁢
1

-

Kf

B
⁢

⁢
1

)

(

f

C
⁢

⁢
1

⁢

C
T

+

Kf

B
⁢

⁢
1

⁢

B
T

)

.

9. The method of claim 5 , further comprising determining a change in pressure with the following equation:

Δ
⁢

⁢
P

=

C
T

C
P

⁢

(

f

C
⁢

⁢
1

⁢

⁢

C
P

+

Kf

B
⁢

⁢
1

⁢

B
P

)

(

Assignees

• Capital Formation Inc
• Quartzdyne Inc

Inventors

• Eernisse Errol P
• Watts Milton

Classifications

• G01L11/04 Primary

  by acoustic means · CPC title

• H03H9/19

  consisting of quartz · CPC title

• E21B47/06

  Measuring temperature or pressure · CPC title

• G01L9/085 Primary

  with temperature compensating means (non electric temperature compensating means G01L19/04) · CPC title

• H01L41/1132

  Electricity · mapped topic